* Conditionals in dtsi files
@ 2015-11-13 9:33 ` Mason
0 siblings, 0 replies; 6+ messages in thread
From: Mason @ 2015-11-13 9:33 UTC (permalink / raw)
To: linux-arm-kernel
Hello,
I'm wondering how much C preprocessor syntax one can use in DT files.
Suppose I have 2 board DTS (both including common.dtsi)
board_A.dts (1-core), board_B.dts (2-core)
Can I have in common.dtsi something along these lines:
cpus {
enable-method = "foo,bar";
#address-cells = <1>;
#size-cells = <0>;
cpu0: cpu at 0 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = <0>;
};
#if CORE_COUNT > 1
cpu1: cpu at 1 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = <1>;
};
#endif
};
board_A.dts would have
#define CORE_COUNT 1
#include "common.dtsi"
board_B.dts would have
#define CORE_COUNT 2
#include "common.dtsi"
Regards.
^ permalink raw reply [flat|nested] 6+ messages in thread* Conditionals in dtsi files
@ 2015-11-13 9:33 ` Mason
0 siblings, 0 replies; 6+ messages in thread
From: Mason @ 2015-11-13 9:33 UTC (permalink / raw)
To: Linux ARM, DT; +Cc: Rob Herring, Grant Likely, Arnd Bergmann
Hello,
I'm wondering how much C preprocessor syntax one can use in DT files.
Suppose I have 2 board DTS (both including common.dtsi)
board_A.dts (1-core), board_B.dts (2-core)
Can I have in common.dtsi something along these lines:
cpus {
enable-method = "foo,bar";
#address-cells = <1>;
#size-cells = <0>;
cpu0: cpu@0 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = <0>;
};
#if CORE_COUNT > 1
cpu1: cpu@1 {
compatible = "arm,cortex-a9";
device_type = "cpu";
reg = <1>;
};
#endif
};
board_A.dts would have
#define CORE_COUNT 1
#include "common.dtsi"
board_B.dts would have
#define CORE_COUNT 2
#include "common.dtsi"
Regards.
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^ permalink raw reply [flat|nested] 6+ messages in thread* Conditionals in dtsi files
2015-11-13 9:33 ` Mason
@ 2015-11-13 9:43 ` Arnd Bergmann
-1 siblings, 0 replies; 6+ messages in thread
From: Arnd Bergmann @ 2015-11-13 9:43 UTC (permalink / raw)
To: linux-arm-kernel
On Friday 13 November 2015 10:33:50 Mason wrote:
> Hello,
>
> I'm wondering how much C preprocessor syntax one can use in DT files.
>
> Suppose I have 2 board DTS (both including common.dtsi)
>
> board_A.dts (1-core), board_B.dts (2-core)
>
> Can I have in common.dtsi something along these lines:
>
> cpus {
> enable-method = "foo,bar";
> #address-cells = <1>;
> #size-cells = <0>;
>
> cpu0: cpu at 0 {
> compatible = "arm,cortex-a9";
> device_type = "cpu";
> reg = <0>;
> };
>
> #if CORE_COUNT > 1
> cpu1: cpu at 1 {
> compatible = "arm,cortex-a9";
> device_type = "cpu";
> reg = <1>;
> };
> #endif
> };
>
>
> board_A.dts would have
> #define CORE_COUNT 1
> #include "common.dtsi"
>
> board_B.dts would have
> #define CORE_COUNT 2
> #include "common.dtsi"
I would prefer not using any preprocessor statements other than
#include in .dts files. It's easy enough to have a per-soc
.dtsi file that defines the CPU nodes and goes on to include another
.dtsi file with the common parts that are present on all SoCs.
Have a look at how the armada-*.dtsi files handle this.
Arnd
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Conditionals in dtsi files
@ 2015-11-13 9:43 ` Arnd Bergmann
0 siblings, 0 replies; 6+ messages in thread
From: Arnd Bergmann @ 2015-11-13 9:43 UTC (permalink / raw)
To: Mason; +Cc: Grant Likely, DT, Linux ARM
On Friday 13 November 2015 10:33:50 Mason wrote:
> Hello,
>
> I'm wondering how much C preprocessor syntax one can use in DT files.
>
> Suppose I have 2 board DTS (both including common.dtsi)
>
> board_A.dts (1-core), board_B.dts (2-core)
>
> Can I have in common.dtsi something along these lines:
>
> cpus {
> enable-method = "foo,bar";
> #address-cells = <1>;
> #size-cells = <0>;
>
> cpu0: cpu@0 {
> compatible = "arm,cortex-a9";
> device_type = "cpu";
> reg = <0>;
> };
>
> #if CORE_COUNT > 1
> cpu1: cpu@1 {
> compatible = "arm,cortex-a9";
> device_type = "cpu";
> reg = <1>;
> };
> #endif
> };
>
>
> board_A.dts would have
> #define CORE_COUNT 1
> #include "common.dtsi"
>
> board_B.dts would have
> #define CORE_COUNT 2
> #include "common.dtsi"
I would prefer not using any preprocessor statements other than
#include in .dts files. It's easy enough to have a per-soc
.dtsi file that defines the CPU nodes and goes on to include another
.dtsi file with the common parts that are present on all SoCs.
Have a look at how the armada-*.dtsi files handle this.
Arnd
^ permalink raw reply [flat|nested] 6+ messages in thread* Conditionals in dtsi files
2015-11-13 9:43 ` Arnd Bergmann
@ 2015-11-13 11:15 ` Mark Rutland
-1 siblings, 0 replies; 6+ messages in thread
From: Mark Rutland @ 2015-11-13 11:15 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Nov 13, 2015 at 10:43:11AM +0100, Arnd Bergmann wrote:
> On Friday 13 November 2015 10:33:50 Mason wrote:
> > Hello,
> >
> > I'm wondering how much C preprocessor syntax one can use in DT files.
> >
> > Suppose I have 2 board DTS (both including common.dtsi)
> >
> > board_A.dts (1-core), board_B.dts (2-core)
> >
> > Can I have in common.dtsi something along these lines:
> >
> > cpus {
> > enable-method = "foo,bar";
> > #address-cells = <1>;
> > #size-cells = <0>;
> >
> > cpu0: cpu at 0 {
> > compatible = "arm,cortex-a9";
> > device_type = "cpu";
> > reg = <0>;
> > };
> >
> > #if CORE_COUNT > 1
> > cpu1: cpu at 1 {
> > compatible = "arm,cortex-a9";
> > device_type = "cpu";
> > reg = <1>;
> > };
> > #endif
> > };
> >
> >
> > board_A.dts would have
> > #define CORE_COUNT 1
> > #include "common.dtsi"
> >
> > board_B.dts would have
> > #define CORE_COUNT 2
> > #include "common.dtsi"
>
> I would prefer not using any preprocessor statements other than
> #include in .dts files.
I very much agree with this.
We should only have (simple) macros for symbolic names, and #includes
required for those to work.
Thanks,
Mark.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: Conditionals in dtsi files
@ 2015-11-13 11:15 ` Mark Rutland
0 siblings, 0 replies; 6+ messages in thread
From: Mark Rutland @ 2015-11-13 11:15 UTC (permalink / raw)
To: Arnd Bergmann; +Cc: Mason, Linux ARM, DT, Rob Herring, Grant Likely
On Fri, Nov 13, 2015 at 10:43:11AM +0100, Arnd Bergmann wrote:
> On Friday 13 November 2015 10:33:50 Mason wrote:
> > Hello,
> >
> > I'm wondering how much C preprocessor syntax one can use in DT files.
> >
> > Suppose I have 2 board DTS (both including common.dtsi)
> >
> > board_A.dts (1-core), board_B.dts (2-core)
> >
> > Can I have in common.dtsi something along these lines:
> >
> > cpus {
> > enable-method = "foo,bar";
> > #address-cells = <1>;
> > #size-cells = <0>;
> >
> > cpu0: cpu@0 {
> > compatible = "arm,cortex-a9";
> > device_type = "cpu";
> > reg = <0>;
> > };
> >
> > #if CORE_COUNT > 1
> > cpu1: cpu@1 {
> > compatible = "arm,cortex-a9";
> > device_type = "cpu";
> > reg = <1>;
> > };
> > #endif
> > };
> >
> >
> > board_A.dts would have
> > #define CORE_COUNT 1
> > #include "common.dtsi"
> >
> > board_B.dts would have
> > #define CORE_COUNT 2
> > #include "common.dtsi"
>
> I would prefer not using any preprocessor statements other than
> #include in .dts files.
I very much agree with this.
We should only have (simple) macros for symbolic names, and #includes
required for those to work.
Thanks,
Mark.
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^ permalink raw reply [flat|nested] 6+ messages in thread
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2015-11-13 9:33 Conditionals in dtsi files Mason
2015-11-13 9:33 ` Mason
2015-11-13 9:43 ` Arnd Bergmann
2015-11-13 9:43 ` Arnd Bergmann
2015-11-13 11:15 ` Mark Rutland
2015-11-13 11:15 ` Mark Rutland
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